In telecommunication systems, signals are transmitted over cables having unshielded twisted pairs of wires. Typical cables have four pairs of twisted wires in them. For connecting wires to other cables or to other apparatus, connectors are mounted on the ends of the cables. These connectors are typically mounted in the field after the cables and wires therein are cut to the appropriate length for the particular installation.
Due to advances in telecommunications and data transmissions, connectors, particularly including plugs, have become a critical impediment to good performance of data transmission at new, higher frequencies. Some performance characteristics, particularly near end crosstalk and return loss, degrade beyond acceptable levels at these higher frequencies.
Performance requirements for conductive pathways are set forth in ANSI/TIA/EIA-568-A, "Commercial Building Telecommunications Cabling Standard". In the Category 6 Draft-Addendum in that standard, the minimum acceptable performance values are 54 dB at 100 MHz, 48 dB at 200/MHz and 46 dB at 250 MHz.
Additionally, in communications systems certain standards have been developed which define connector geometry and pin out definitions. These standards were created prior to the need for high speed data communications, and have created a large installed base of wiring connectors. Additionally, these standards have created a need for connectors capable of maintaining the requirements of higher speed communications, while maintaining compatibility with original connectors.
The standard connector geometry and pin outs can generate a great deal of crosstalk at higher signal frequencies. Connectors addressing this problem include U.S. Pat. No. 5,432,484 to Klas et al and U.S. Pat. No. 5,414,393 to Rose et al, this subject matters of which are hereby incorporated by reference.
In addition to the crosstalk reduction provided by the inventions of the above cited patents, crosstalk generated at the connection between the cable wires and the connectors, particularly the plug connectors has become significant. Variations in the placement of the wiring creates a varying amounts of crosstalk. Additionally, the wires must be accurately and precisely located within the connector to facilitate termination by the insulation displacement contacts.